/***************************************************************************/
/*                                                                         */
/*  ftcmanag.h                                                             */
/*                                                                         */
/*    FreeType Cache Manager (specification).                              */
/*                                                                         */
/*  Copyright 2000-2001, 2003, 2004, 2006 by                               */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


/*************************************************************************/
/*                                                                       */
/* A cache manager is in charge of the following:                        */
/*                                                                       */
/*  - Maintain a mapping between generic FTC_FaceIDs and live FT_Face    */
/*    objects.  The mapping itself is performed through a user-provided  */
/*    callback.  However, the manager maintains a small cache of FT_Face */
/*    and FT_Size objects in order to speed up things considerably.      */
/*                                                                       */
/*  - Manage one or more cache objects.  Each cache is in charge of      */
/*    holding a varying number of `cache nodes'.  Each cache node        */
/*    represents a minimal amount of individually accessible cached      */
/*    data.  For example, a cache node can be an FT_Glyph image          */
/*    containing a vector outline, or some glyph metrics, or anything    */
/*    else.                                                              */
/*                                                                       */
/*    Each cache node has a certain size in bytes that is added to the   */
/*    total amount of `cache memory' within the manager.                 */
/*                                                                       */
/*    All cache nodes are located in a global LRU list, where the oldest */
/*    node is at the tail of the list.                                   */
/*                                                                       */
/*    Each node belongs to a single cache, and includes a reference      */
/*    count to avoid destroying it (due to caching).                     */
/*                                                                       */
/*************************************************************************/


/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*********                                                       *********/
/*********             WARNING, THIS IS BETA CODE.               *********/
/*********                                                       *********/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
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/*************************************************************************/


#ifndef __FTCMANAG_H__
#define __FTCMANAG_H__


#include <ft2build.h>
#include FT_CACHE_H
#include "ftcmru.h"
#include "ftccache.h"


FT_BEGIN_HEADER


/*************************************************************************/
/*                                                                       */
/* <Section>                                                             */
/*    cache_subsystem                                                    */
/*                                                                       */
/*************************************************************************/


#define FTC_MAX_FACES_DEFAULT 2
#define FTC_MAX_SIZES_DEFAULT 4
#define FTC_MAX_BYTES_DEFAULT 200000L   /* ~200kByte by default */

/* maximum number of caches registered in a single manager */
#define FTC_MAX_CACHES 16


typedef struct  FTC_ManagerRec_
{
    FT_Library library;
    FT_Memory memory;

    FTC_Node nodes_list;
    FT_ULong max_weight;
    FT_ULong cur_weight;
    FT_UInt num_nodes;

    FTC_Cache caches[FTC_MAX_CACHES];
    FT_UInt num_caches;

    FTC_MruListRec faces;
    FTC_MruListRec sizes;

    FT_Pointer request_data;
    FTC_Face_Requester request_face;

} FTC_ManagerRec;


/*************************************************************************/
/*                                                                       */
/* <Function>                                                            */
/*    FTC_Manager_Compress                                               */
/*                                                                       */
/* <Description>                                                         */
/*    This function is used to check the state of the cache manager if   */
/*    its `num_bytes' field is greater than its `max_bytes' field.  It   */
/*    will flush as many old cache nodes as possible (ignoring cache     */
/*    nodes with a non-zero reference count).                            */
/*                                                                       */
/* <InOut>                                                               */
/*    manager :: A handle to the cache manager.                          */
/*                                                                       */
/* <Note>                                                                */
/*    Client applications should not call this function directly.  It is */
/*    normally invoked by specific cache implementations.                */
/*                                                                       */
/*    The reason this function is exported is to allow client-specific   */
/*    cache classes.                                                     */
/*                                                                       */
FT_LOCAL(void)
FTC_Manager_Compress(FTC_Manager manager);


/* try to flush `count' old nodes from the cache; return the number
 * of really flushed nodes
 */
FT_LOCAL(FT_UInt)
FTC_Manager_FlushN(FTC_Manager manager,
                   FT_UInt count);


/* this must be used internally for the moment */
FT_LOCAL(FT_Error)
FTC_Manager_RegisterCache(FTC_Manager manager,
                          FTC_CacheClass clazz,
                          FTC_Cache * acache);

/* */

#define FTC_SCALER_COMPARE(a, b) \
    ((a)->face_id == (b)->face_id && \
     (a)->width == (b)->width && \
     (a)->height == (b)->height && \
     ((a)->pixel != 0) == ((b)->pixel != 0) && \
     ((a)->pixel || \
      ((a)->x_res == (b)->x_res && \
       (a)->y_res == (b)->y_res)))

#define FTC_SCALER_HASH(q) \
    (FTC_FACE_ID_HASH((q)->face_id) + \
     (q)->width + (q)->height * 7 + \
     ((q)->pixel ? 0 : ((q)->x_res * 33 ^ (q)->y_res * 61)))

/* */

FT_END_HEADER

#endif /* __FTCMANAG_H__ */


/* END */